China's foreign minister to visit Washington: Beijing

China said its Foreign Minister Wang Yi would visit Washington on Wednesday, as trade tensions ease but new strains arise over North Korea and Beijing's military moves in the South China Sea.

"China and the US will exchange views on bilateral relations and issues of common interest," said foreign ministry spokesman Lu Kang, announcing the visit Tuesday.

Wang is stopping over in the US capital on his way home from Argentina, where he is attending a G20 foreign ministers' meeting and has reportedly discussed contentious South China Sea issues with some of his counterparts.

Tensions have risen since China flew nuclear-capable bombers to a disputed island in the South China Sea last week.

The Pentagon condemned Beijing's "continued militarisation of disputed features" in the waterway.

Meanwhile, US President Donald Trump has urged China to maintain tight control over its border with North Korea until he signs a denuclearisation deal with Kim Jong Un. A summit is set for June 12.

"The word is that recently the Border has become much more porous and more has been filtering in," Trump tweeted Monday.

The two nations may also lock horns over China's business ties with Iran after Trump pulled the US out of the Iran nuclear deal and said he would reimpose sanctions.

China voiced regret at the decision and vowed to "safeguard" the agreement.